In climatology, we talk about internal and external causes of climate variations. These can include things like how much sunlight is hitting the earth, volcanic eruptions, cloud coverage across the globe, and changes in the land surface. Here is an insightful article describing how internal and external variability in climate are both important but different factors in determining future climate. It’s done in a fun way using bears and butterflies, so it should be understandable to most people. You can read it at https://www.climate.gov/news-features/blogs/enso/variable-walks-our-climate-forest.
